Patent application title: BATTERY PACK

Abstract:

A battery pack to improve assembling reliability in a battery with a cover
frame. The battery pack according to the present invention includes a
rechargeable battery having at least one rounded lateral side; a cover
frame including a frame surrounding each of lateral sides of the
rechargeable battery, wherein more than at least one groove is formed at
both ends of the frame covering the rounded lateral side of the
rechargeable battery. Therefore, it is possible to couple the cover frame
to the rechargeable battery via the groove without deforming the cover
frame. Also, the rounded battery and the rounded cover frame closing each
other is an effect that assembly error of a battery to cover frame can be
reduced.

Claims:

1. A battery pack comprising:a rechargeable battery having at least one
rounded lateral side; anda cover frame including sides surrounding each
lateral side of the rechargeable battery, wherein at least one groove is
formed at both ends of the side that covers the rounded lateral side of
the rechargeable battery.

2. The battery pack according to claim 1, wherein one side of the cover
frame that is in contact with the rounded lateral side of the
rechargeable battery is a rounded side to surround the rounded lateral
side.

3. The battery pack according to claim 1, wherein the rechargeable battery
is a square shape as seen from a front of a wide side of the rechargeable
battery, and the cover frame is formed in a square shape surrounding a
narrow lateral side of the rechargeable battery.

4. The battery pack according to claim 1, wherein the cover frame is
formed of thermoplastic resin.

5. The battery pack according to claim 1, further comprising a protection
circuit board arranged between one of the sides of the cover frame and
the battery, on which a charging/discharging terminal is formed;
andwherein a hole to accommodate the charging/discharging terminal is
formed in any one of the sides of the cover frame.

6. The battery pack according to claim 5, further comprising an insulator
to insulate the protection circuit board arranged between the protection
circuit board and the rechargeable battery.

7. The battery pack according to claim 5, further comprising a mount case
to mount the protection circuit board and arranged between the protection
circuit board and the rechargeable battery.

8. The battery pack according to claim 1, further comprising a label
surrounding a region in which the side having the groove is in contact
with the rechargeable battery.

9. The battery pack according to claim 1, wherein the rechargeable battery
comprising:an electrode assembly;a can to accommodate the electrode
assembly via an opening and having at least one rounded side; anda cap
assembly to cover the opening the can.

10. The battery pack according to claim 1, wherein the rechargeable
battery comprising:an electrode assembly; anda pouch to accommodate the
electrode assembly by sealing and having at least one rounded side.

11. A battery pack comprising:a rechargeable battery having at least one
rounded lateral side; anda cover frame including sides surrounding each
of the lateral sides of the rechargeable battery, wherein one side of the
cover frame that is in contact with the rounded lateral side of the
rechargeable battery is a rounded side surrounding the rounded lateral
side.

12. The battery pack according to claim 11, wherein at least one groove is
formed at both ends of the side covering the rounded lateral side of the
rechargeable battery.

13. The battery pack according to claim 11, wherein:the rechargeable
battery has a square shape as seen from a front of a wide side of the
rechargeable battery; andthe cover frame is formed in a square shape
surrounding a narrow lateral side of the rechargeable battery.

14. The battery pack according to claim 11, wherein the cover frame is
formed of thermoplastic resin.

15. The battery pack according to claim 11, further comprising a
protection circuit board arranged between one of the sides of the cover
frame and the battery, on which a charging/discharging terminal is
formed; andwherein a hole to accommodate the charging/discharging
terminal is formed in one of the sides of the cover frame.

16. The battery pack according to claim 15, further comprising an
insulator to insulate the protection circuit board arranged between the
protection circuit board and the rechargeable battery.

17. The battery pack according to claim 15, further comprising a mount
case to mount the protection circuit board and arranged between the
protection circuit board and the rechargeable battery.

18. The battery pack according to claim 11, further comprising a label
surrounding a region in which the side having the groove is in contact
with the rechargeable battery.

19. The battery pack according to claim 11, wherein the rechargeable
battery comprises:an electrode assembly;a can to accommodate the
electrode assembly via an opening and having at least one rounded side;
anda cap assembly to cover the opening the can.

20. The battery pack according to claim 11, wherein the rechargeable
battery comprises:an electrode assembly; anda pouch to accommodate the
electrode assembly by sealing and having at least one rounded side.

21. A battery pack comprising:a rechargeable battery having at least one
rounded side;a cover frame coupled to the rechargeable battery and having
at least one rounded side corresponding to the rounded side of the
rechargeable battery and a groove to prevent the rounded frame that is in
contact with the rounded side from being deformed when the rechargeable
battery is inserted into the cover frame; andan adhesive label
surrounding the rounded side of the cover frame to adhere the cover frame
to the rechargeable battery.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001]This application claims priority to and the benefit of Korean Patent
Application No. 2007-109725 filed in the Korean Intellectual Property
Office on Oct. 30, 2007, the disclosure of which is incorporated herein
by reference.

BACKGROUND OF THE INVENTION

[0002]1. Field of the Invention

[0003]Aspects of the present invention relates to a secondary battery and,
more particularly to a structure of a battery pack for coupling a
secondary battery.

[0004]2. Description of the Related Art

[0005]Recently, compact, light-weight and portable electronic devices,
such as cellular phones, notebook computers, camcorders, and the like,
are being developed and produced briskly. These portable electronic
devices include a battery pack so that the devices can be operated even
where additional power sources are not provided. Currently, the battery
pack employs a secondary battery in which charging/discharging can be
executed when taking the economic aspects into consideration. A Ni--Cd
battery, a Ni-MH battery, a Li battery and a Li-ion secondary battery are
examples of typical secondary batteries. The operation voltage of the
Li-ion secondary battery is approximately three times higher than those
of the Ni--Cd battery and the Ni-MH battery, which are widely used as the
power sources of the portable electronic devices. In addition, Li-ion
secondary batteries are widely used since the energy density per unit
weight for Li-ion secondary batteries is very high.

[0006]The secondary battery usually employs a Li-based oxide as positive
electrode active material and a carbonic material as negative electrode
active material. Generally, the secondary battery is classified into a
liquid electrolyte battery and a high-polymer electrolyte battery
according to the kind of electrolyte. A battery using the liquid
electrolyte is called a lithium ion battery, and a battery using the
high-polymer electrolyte is called a lithium polymer battery. A lithium
secondary battery is formed in various kinds of shapes, such as a
cylindrical shape, a square shape, and a pouch shape.

[0007]Among the secondary batteries having these shapes, the edges of the
secondary battery in a square shape may be crushed due to shocks during
assembly and/or use. In order to prevent this problem, the secondary
battery may be used after coupling a cover frame to a battery that covers
the edges of the secondary battery.

[0008]The secondary battery has a rounded lateral side surface, and thus
assembling the secondary battery with the cover frame is difficult due to
the lateral rounded side surface. The assembly workers push the battery
into the cover frame, and as a result, the cover frame is deformed
inelastically. Moreover, because the cover frame does not return to the
first shape due to the deformation, reassembling the secondary battery
with the cover frame is difficult.

[0009]Also, a rounded side surface of the secondary battery with which the
cover frame is in contact is depressed, affecting assembling reliability
of the cover frame.

SUMMARY OF THE INVENTION

[0010]Aspects of the present invention provide a battery pack having a
cover frame coupled to a battery without generating a plastic deformation
of the cover frame.

[0011]According to an aspect of the present invention, a battery pack is
provided. The battery pack includes a rechargeable battery having at
least one rounded lateral side; a cover frame including sides surrounding
each lateral side of the rechargeable battery, wherein at least one
groove is formed at both ends of the side that covers the rounded lateral
side of the rechargeable battery. According to another aspect of the
invention, one side of the cover frame that is in contact with the
rounded lateral side of the rechargeable battery is a rounded side to
surround the rounded lateral side.

[0012]According to another aspect of the present invention, a battery pack
is provided. The battery pack includes a rechargeable battery having at
least one rounded lateral side; and a cover frame including sides
surrounding each of the lateral sides of the rechargeable battery,
wherein one side of the cover frame that is in contact with the rounded
lateral side of the rechargeable battery is a rounded side surrounding
the rounded lateral side. According to another aspect of the present
invention, at least one groove is formed at both ends of the side
covering the rounded lateral side of the rechargeable battery.

[0013]According to another aspect of the present invention, the
rechargeable battery is a square shape as seen from a front of a wide
side of the rechargeable, and the cover frame is formed in a square shape
for surrounding a narrow lateral side of the rechargeable battery.

[0014]According to another aspect of the present invention, the groove is
formed in a square shape or an arc shape.

[0015]According to another aspect of the present invention, the cover
frame is formed by a thermoplastic resin.

[0016]According to another aspect of the present invention, a hole for a
charging/discharging terminal is formed in a side of the cover frame.

[0017]According to another aspect of the present invention, the battery
pack includes a protection circuit board arranged between one of the
sides of the cover frame and the battery, on which a charging/discharging
terminal is formed, wherein a hole to accommodate the
charging/discharging terminal is formed in a frame of the cover frame.

[0018]According to another aspect of the present invention, an insulator
to insulate the protection circuit board is arranged between the
protection circuit board and the rechargeable battery.

[0019]According to another aspect of the present invention, a mount case
to mount the protection circuit board is arranged between the protection
circuit board and the rechargeable battery.

[0020]According to another aspect of the present invention, the battery
pack includes a label surrounding a region in which the side having the
groove is in contact with the rechargeable battery.

[0021]According to another aspect of the present invention, the
rechargeable battery is a can type rechargeable battery.

[0022]According to another aspect of the present invention, the
rechargeable battery is a pouch type rechargeable battery.

[0023]Additional aspects and/or advantages of the invention will be set
forth in part in the description which follows and, in part, will be
obvious from the description, or may be learned by practice of the
invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024]These and/or other aspects and advantages of the invention will
become apparent and more readily appreciated from the following
description of the embodiments, taken in conjunction with the
accompanying drawings of which:

[0025]FIG. 1A is an exploded perspective view illustrating a battery pack
according to an embodiment of the present invention;

[0026]FIG. 1B is a plane view illustrating a state that a cover frame is
pulled into one direction for coupling a battery to the cover frame of
FIG. 1A;

[0027]FIG. 1C is a cross-sectional view taken along I-I line of FIG. 1A;

[0028]FIG. 1D is a plane view illustrating battery coupled to a cover
frame of FIG. 1A;

[0029]FIG. 2 is an exploded perspective view illustrating a battery, a
cover frame, and a coupling auxiliary according to another embodiment of
the present invention;

[0030]FIG. 3 is an exploded perspective view illustrating a battery pack
according to still another embodiment of the present invention;

[0031]FIG. 4A is a perspective view illustrating a can type rechargeable
battery according to still another embodiment of the present invention;

[0032]FIG. 4B is an exploded perspective view illustrating the can type
rechargeable battery of FIG. 4A;

[0033]FIG. 5A is an perspective view illustrating a pouch type
rechargeable battery according to still another embodiment of the present
invention; and

[0035]Reference will now be made in detail to the present embodiments of
the present invention, examples of which are illustrated in the
accompanying drawings, wherein like reference numerals refer to the like
elements throughout. The embodiments are described below in order to
explain the present invention by referring to the figures.

[0036]FIG. 1A is an exploded perspective view illustrating a battery pack
100 according to an embodiment of the present invention. The battery pack
100 includes a battery 110 and a cover frame 120. According to other
aspects of the present invention, the battery pack may include additional
components.

[0037]The battery 110 is formed of at least one round surface 111 among
several lateral sides. The battery 110 may be formed with two wide
surfaces facing each other and three narrow surface connecting the two
wide surfaces. In this case, at least two of the narrow surfaces are the
respective round surfaces 111.

[0038]The cover frame 120 includes a frame surrounding each of the lateral
sides of the battery 110. More than one groove 125 may be formed at both
ends of the frame covering the lateral side of the battery 110 on which a
round surface 111 is formed. The cover frame 120 surrounds the lateral
sides of the battery 110, and surrounds the battery 110 in order to
protect the battery 110 from external shocks.

[0039]The cover frame 120 may be coupled to several batteries at once
since each side 121, 122, 123, 124 of the cover frame surrounding the
batteries are integrally formed. In this case, the groove 125 in a square
shape or an arc shape may be formed at both ends of the frame that is in
contact with the rounded lateral sides 111 of the battery 110. The groove
125 prevents both ends of the frame in contact with the rounded lateral
side 111 of the battery 110 from being plastic-deformed when the battery
110 is inserted into the cover frame 120.

[0040]FIG. 1B is a plane view of a state that a cover frame is pulled into
one direction for coupling the battery 110 to the cover frame 120 shown
in FIG. 1a. The battery 110 is coupled to the cover frame 120 while the
side 121 in contact with a rounded lateral side of a battery (not shown)
is opened in a direction indicated by the arrow. If the groove 125 is not
formed, a plastic deformation may be generated at both ends of the side
121 when the side 121 is stretched, thereby generating an assembling
error between the cover frame 120 and the battery. By forming the groove
125, the cover frame 120 is not deformed inelastically and the cover
frame 120 can be returned to its original shape.

[0041]FIG. 1C is a cross-sectional view taken along I-I line of FIG. 1a.
One side 126 of the cover frame 120 covering a rounded lateral side of a
battery (not shown) may be rounded so as to surround the rounded lateral
side. When the rounded lateral side of the battery 110 and the cover
frame 120 are coupled, a rounded lateral side of the cover frame 120 may
cover the rounded lateral side of a battery in order to minimize the gap
between the battery 110 and the cover frame 120. Thus, the assembling
force of the battery (not shown) and cover frame 120 can be improved.
Also, assembling error of the battery and the cover frame 120 can be
reduced.

[0042]FIG. 1D is a plane view showing the battery 110 coupled to the cover
frame 120. The battery 110 is a square shape as seen from the front of a
wide side of the battery 110. The cover frame 120 may be formed in a
square shape surrounding narrow lateral sides of the battery. As the size
of the portable electronic devices is getting smaller and thinner, the
thickness of the battery mounted in the portable electronic devices is
getting thinner and is being widely used in a square shape in which
excellent insertion is realized. However, in terms of the structure,
there exists a problem that the edges of the battery 110 having such a
structure are crushed flat due to the external shock or force of
insertion. The edges of the battery 110 may be protected by surrounding
the narrow lateral side of the battery 110 using the cover frame 120 in
order to solve this shortcoming. The cover frame 120 is also formed in a
square shape surrounding the narrow lateral side of the battery 110.

[0043]The cover frame 120 may be formed of a thermoplastic resin. The
cover frame 120 may be formed by an injection molding. The cover frame
120 may be formed by converting the original material into a
thermoplastic resin having an elastic force and a restoring force. Among
the thermoplastic resins, materials having excellent elasticity and
anti-shock property, such as a polyethylene or an ABS resin that is not
inflammable, may be employed.

[0044]FIG. 2 is an exploded perspective view of a battery pack 200,
including the battery 110, the cover frame 120, and a coupling auxiliary
(insulating body) 220, according to another embodiment of the present
invention. As shown in FIG. 2, a protection circuit board 210 is
electrically coupled with a positive electrode 110a and a negative
electrode 110b of the battery 110. The protection circuit board 210 may
be formed with a charging/discharging terminal 211. In this case, a hole
212 for the charging/discharging terminal 211 is formed in one of the
frames of the cover frame 120. The hole 212 exposes a terminal side of
the charging/discharging terminal 211 of the protection circuit board 210
to the outside. The charging/discharging terminal 211 is coupled to a
load or a charging device, thereby charging/discharging the battery pack
200. The protection circuit board 210 contains electrical elements
including passive elements (not shown), active elements (not shown), and
a protection circuit (not shown). These electrical elements may be welded
to a print circuit pattern (not shown) formed on the upper side and the
lower side of an insulating substrate 213.

[0045]The protection circuit board 210 may be electrically coupled to a
positive electrode and a negative electrode of the battery 110 by a
positive/negative lead tab 214. A protection circuit of the protection
circuit board 210 electrically coupled to the battery 110 is electrically
coupled to the active elements and the passive elements to control all
kinds of states of the battery 110 and to check the remaining charge of
the battery 110. Charging or discharging may be controlled by selecting a
suitable charging method according to the charging/discharging state of a
secondary battery. The protection circuit stores information about the
battery 110, such as a voltage, a current, a temperature, a remaining
charge, and the like, and transmits the information to external devices.
The protection circuit may be an integrated circuit in which a plurality
of logic elements and active/passive elements are integrated.

[0046]A positive/negative display groove 215 may be formed around the hole
212 formed in the cover frame 120. The positive/negative display groove
215 displays a positive electrode and a negative electrode of the
charging/discharging terminal 211 so that polarity information of a
battery pack may be notified to a user.

[0047]An insulating body 220 for insulating the protection circuit board
210 may be formed between the protection circuit board 210 and the
battery 110. The insulating body 220 insulates the protection circuit
board 210 and the battery 110 to prevent a short between the protection
circuit board 210 and the battery 110. The insulating body 220 may be
formed of resins, such as polypropylene or polyethylene or the like.
However, the present invention is not limited thereto; the insulating
body 120 may be composed of any insulating material. The insulating body
220 may be formed in a variety of shapes according to a lateral shape of
the battery 110.

[0048]A positive/negative coupling hole 221 may be formed in the
insulating body 220 to couple the protection circuit board 210 to the
positive electrode and the negative electrode of the battery 110. A
positive/negative lead tab 214 electrically coupled to the protection
circuit board 210 may be electrically coupled to the positive electrode
110a and negative electrode 110b via the positive/negative coupling hole
221.

[0049]A mounting case 230 for mounting the protection circuit board 210
may be formed between the protection circuit board 230 and the battery
110. The mounting case 230 forms a protrusion 231 so that the mounting
case 230 may be hooked to a hook hole 232 formed in the cover frame 120.
Here, the cover frame 120 and the protection circuit board 210 are
coupled integrally by mounting the protection circuit board 210. In
particular, the mounting case 230 supports the protection circuit board
210 so that a terminal side of the charging/discharging terminal 211
formed in the protection circuit board 210 is coupled to the hole 212 for
charging/discharging terminal formed in the cover frame 120 correctly. In
the mounting case 230, lateral walls 233 are formed for mounting the
protection circuit board 210, and a hole 234 may be formed for securing a
space on which the electrical elements mounted in the protection circuit
board 210 are positioned.

[0050]FIG. 3 is an exploded perspective view showing a battery pack 300
according to still another embodiment of the present invention. The
battery pack 300 includes a battery 110, a cover frame 120 and a label
310.

[0051]The label 310 adheres the rounded side 121 formed by the groove 125
to the wide surface 301 of the battery 110. As a result, a coupling force
between the battery 110 and cover frame 120 is improved by the label 310.
The adhesive may be polypropylene or polyethylene so that the battery and
the cover frame may be coupled. However, the present invention does not
limit the materials and the structure of the label 310.

[0052]FIG. 4A is a perspective view showing a can type rechargeable
battery 400 according to still another embodiment of the present
invention. FIG. 4B is an exploded perspective view showing the can type
rechargeable battery 400.

[0053]Referring to FIG. 4A, a battery 400 using the battery pack is formed
as a can type rechargeable battery. The can type rechargeable battery 400
may be recharged and formed with at least one rounded lateral side
formed.

[0054]The can type rechargeable battery 400 may include an electrode
assembly 410, a can 420, and a cap assembly 430. The electrode assembly
410 may be formed by stacking a positive electrode plate 411 to which a
positive electrode tab 415 is coupled, a negative electrode plate 412 to
which a negative electrode tab 415 is coupled, and a separator 413, and
then winding the positive electrode plate 411, the separator 413, and the
negative electrode plate 412.

[0055]The positive electrode plate 411 includes a positive electrode
collector and a positive electrode coating portion. The positive
electrode coating portion may be composed of a layered compound
containing a lithium compound, a binder for improving a bonding strength,
and a conductive material for improving conductivity. Generally, aluminum
is used as the positive electrode collector; however, other materials may
be used as well. The positive electrode collector is used as a path
through which charges generated in the positive electrode coating portion
move, and supports the positive electrode coating portion. The positive
electrode coating portion is attached over the wide sides of the positive
electrode collector. A positive electrode non-coating portion (not shown)
on which the positive electrode coating portion is not formed is formed
on a lateral side of the positive electrode plate 411. The positive
electrode tab 414 is coupled to the positive electrode non-coating
portion.

[0056]The negative electrode plate 412 includes a negative electrode
collector and a negative electrode coating portion. The negative
electrode coating portion may be composed of hard carbon or graphite
containing carbon and a binder for improving bonding strength between
active material particles. In general, the negative electrode collector
is formed of copper, and serves as a passage for an electric charge
generated from the negative electrode coating portion, though other
materials may be used as well. The negative electrode collector supports
the negative electrode coating portion. The negative electrode coating
portion is formed on a wide surface of the negative electrode plate. A
negative electrode non-coating portion (not shown), in which the negative
electrode coating portion is not formed, is formed at one end of the
negative electrode plate 412. The negative electrode tab 415 is connected
to the negative electrode non-coating portion.

[0057]The separator 413 interposed between the positive electrode plate
411 and the negative electrode plate 412 insulates the positive electrode
plate 411 from the negative electrode plate 412, but transmits charges of
the positive electrode plate 411 and the negative electrode plate 412.
The separator is generally formed of polyethylene (PE) or polypropylene
(PP), but other materials may be used as well. When the separator 413 is
a separator for a lithium-polymer battery, air holes may be formed in the
separator 413, and thus the separator 413 may include the air holes and
the polymer electrolyte.

[0058]The can 420 has one end side open to accommodate the electrode
assembly 410. The can 420 may be formed in a square shape or an elliptic
shape, based on the shape of the electrode assembly 410. The can 420
accommodates an insulating case 436 on the upper side of the electrode
assembly 410. The insulating case 436 is coupled to the can 420 by
covering a cap plate 431 on an opening of the can 420, and then welding
the insulating case 436 to the can 420. Generally, aluminum is used as
the material of the can 420, though other materials may be used as well.
A lateral side 421 of the can 420 may be round. The can 420 may be formed
with two wide surfaces facing each other and three narrow surface
connecting the two wide surfaces. In this case, at least two of the
narrow surfaces are respective rounded surfaces 421.

[0059]The cap assembly 430 includes a cap plate 431, an electrode terminal
432, an insulating gasket 433, the insulating case 436, a terminal plate
434, and an insulating plate 435. The cap plate 431 covers the opening of
the can 420, and includes an electrolyte injection hole lid 431a formed
on the upper side thereof to seal an electrolyte injection hole 431a, a
safety vent 431c to open the can so as to prevent an explosion, and is
thus electrically coupled to the positive electrode tab 414. The
electrode terminal 432 is mounted in a middle hole of the cap plate 431
and electrically coupled to the negative electrode tab 415. The
insulating gasket 433 insulates the electrode terminal 432 and the cap
plate 431 by surrounding a body of the electrode terminal 432. The
insulating case 436 includes a hole to project the positive electrode tab
414 and the negative electrode tab 415, and is mounted on the upper side
of the electrode assembly 410 to insulate the upper surface of the
electrode assembly 410. The terminal plate 434 provides a hole to allow
an end of the electrode terminal 432 to be pressed and then fixed. The
insulating plate 435 insulates the terminal plate 434 and the cap plate
431.

[0060]The insulating gasket 433, the insulating case 436, and the
insulating plate 435 may be formed of insulating materials, such as
polyethylene resin or polypropylene resin or the like. The electrode
terminal 432, the cap plate 431, and the terminal plate 434 may be formed
of conductive metals, such as aluminum or nickel, or an alloy including a
conductive metal and so on. However, any materials or structure of the
cap assembly 430 may be employed.

[0061]FIG. 5A is a perspective view illustrating a pouch type rechargeable
battery 500 according to still another embodiment of the present
invention. FIG. 5B is an exploded perspective view illustrating the pouch
type rechargeable battery 500.

[0062]As shown in FIG. 5A, a battery using the battery pack of the present
invention may be formed as the pouch type rechargeable battery 500. The
pouch type rechargeable battery 500 may be recharged, and at least one
lateral side of the pouch type rechargeable battery 500 may be rounded.

[0063]As shown in FIG. 5B, the pouch type rechargeable battery 500
includes a electrode assembly 410 and a pouch 510. The electrode assembly
410 may be an electrode assembly used for the can type rechargeable
battery 400. The separator 413 used may contain a polymer electrolyte.
The electrode assembly 410 used for the pouch type rechargeable battery
400 may be an electrode assembly for a lithium polymer battery.

[0064]The pouch 510 accommodates the electrode assembly 410 with the
positive electrode tab 414 and the negative electrode tab 415 exposed
therefrom. The pouch 510 may be formed of a multi-layer film. In the
multi-layer film, a thermal adhesive layer (not shown), which is an inner
layer, may be formed of CPP (casted polypropylene), an intermediate
barrier layer (not shown) may be formed of an aluminum layer, and an
outer protection layer (not shown) may be formed of a nylon layer. The
pouch 510 may include a lower film 511 having a groove 511a to
accommodate the electrode assembly 410 formed therein and an upper film
512 to seal an opening of the lower film 511. The lower film 511 and the
upper film 512 are bonded to each other by heating the thermal adhesive
layer, which is a contact portion between the lower film 511 and the
upper film 512. A positive electrode/negative electrode insulating tape
520 interposed between the lower film 511 and the upper film 512 may be
attached to the pouch 510 by applying heat. However, the structure of the
pouch and materials forming the pouch are not limited to the above. After
the pouch 510 accommodates the electrode assembly 410, the pouch 510
folds an external sealing region, and the external sealing region may be
a round region. As shown in FIG. 5A, the sealing portion of the external
sealing region folded of FIG. 5A is a rounded portion 510a.

[0065]As the battery pack according to aspects of the present invention
includes a groove in a cover frame for restoring the cover frame to a
former state, the battery back is easily assembled without damage. Also,
the battery pack according to aspects of the present invention is formed
with a rounding in a cover frame in which a rounded surface of a battery
is assembled, thus improving reliability in assembling a battery with a
cover frame.

[0066]Although a few embodiments of the present invention have been shown
and described, it would be appreciated by those skilled in the art that
changes may be made in this embodiment without departing from the
principles and spirit of the invention, the scope of which is defined in
the claims and their equivalents.